The present invention provides a gellation resistant aqueous glycol or glycol ether composition containing a phosphorous modified silane.
Antifreeze compositions containing glycols and various corrosion inhibitors are well known in the prior art as is illustrated by U.S. Pat. Nos. 3,282,846 dated Nov. 1, 1966, and 3,362,910 dated Jan. 9, 1968. The use of the relatively inexpensive and effective borax and silicates in glycol formulations is well illustrated by these patents. It is conventional in this art to make a glycol concentrate which is then sold to end users for use as a coolant in automotive radiators and the like after dilution with water.
In the past, it has been found that glycol concentrates prepared using conventional corrosion inhibitors such as borax and silicates had a tendency to develop irreversible silicate gels upon standing for a period of time in a warehouse or a store. The end user, when he attempted to pour the glycol concentrate into his automotive radiator found that the concentrate had developed "slugs" or gels which either did not pour readily or which tumbled out in discrete masses along with the liquid. The present invention was developed to eliminate this gel formation.
In U.S. Pat. No. 4,149,985 dated Apr. 17, 1979, there is disclosed that a gellation resistant glycol composition containing borate and silicate additives can be made wherein the order of addition of the additives and the pH of the solution is closely controlled in order to obtain the gellation resistant formulation. This is difficult to control during production.
In Ser. No. 191,798 filed Sept. 29, 1980 now U.S. Pat. No. 4,287,077 dated Sept. 1, 1981, there is disclosed a gellation resistant glycol composition which contains an effective amount of a silicone containing polyoxyalkylene functionality. While these silicone compounds are effective, it has been found that production of glycol compositions containing these compounds is limited to the addition of the compounds before the addition of the alkali metal silicates which are present in the glycol compositions to enhance the corrosion resistance of the compositions. The present invention is thus more useful in that the phosphorous-silane compounds can be added anytime during production.
In British Pat. No. 2,018,266A dated Oct. 17, 1979, there is disclosed the use of alkali metal salts of polymeric silylalkylphosphonates as metal corrosion inhibitors for alcoholic or glycolic compositions.
In Ser. No. 198,973 filed Oct. 20, 1980, now U.S. Pat. No. 4,333,843 dated June 8, 1982 there is disclosed glycol compositions which are gellation resistant due to the use of an effective amount of the hydrolyzate of compounds having the formula EQU (RO).sub.3 Si--(CH.sub.2).sub.n --O--P(O)(CH.sub.3)--OR
where R is an alkyl group of 1-4 carbons and n is an integer of 1-4. It is believed that these hydrolyzates are the same polymers described in the above British patent. However, the commercial use of these polymers is severely curtailed by their high cost.
U.S. Pat. No. 3,121,692 (dated Feb. 18, 1964) (Cols. 18 & 19) discloses gellation resistant glycol formulations containing sodium silicate and amino silanes. However, it has been found that the compounds used herein are much more effective than the patented amino silanes as anti-gellation additives.
The following patents show related compositions containing slioxanes and the storage stability thereof but they do not show the use of alkali metal silicates, glycol, and gellation inhibitors.
U.S. Pat. No. 3,234,144 (dated Mar. 26, 1962) Col. 12 PA1 U.S. Pat. No. 3,248,329 (dated Apr. 26, 1966) Col. 19 PA1 U.S. Pat. No. 3,312,622 (dated Apr. 4, 1967) Col. 21 & 22 PA1 U.S. Pat. No. 3,337,496 (dated Aug. 22, 1967) Col. 9 PA1 U.S. Pat. No. 3,341,469 (dated Sept. 12, 1967) Col. 9 PA1 (I) (RO).sub.3-m (R').sub.m Si--R.sup.2 --O--P(O)(OR.sup.3)(R.sup.4), PA1 (II) [(RO).sub.3-m (R').sub.m Si--R.sup.2 --O--].sub.2 P(O)(R4), or PA1 (III) mixtures of I and II, PA1 wherein m is 0-2 PA1 (I) (RO).sub.3-m (R').sub.m Si--R.sup.2 --O--P(O)(OR.sup.3)(R.sup.4), PA1 (II) [(RO).sub.3-m (R').sub.m Si--R.sup.2 --O--].sub.2 P(O)(R4), or PA1 (III) mixtures of I and II, PA1 wherein m is 0-2 PA1 (I) (RO).sub.3 Si--(--CH.sub.2).sub.n O-P(O)(CH.sub.3)--OR, PA1 (II) [(RO).sub.3 Si--(--CH.sub.2).sub.n O--].sub.2 --P(O)(CH.sub.3), or PA1 (III) mixtures of I and II,